just refactor

app/src/main/java/chat/rocket/android/RocketChatCache.java

@@ -12,7 +12,7 @@ public class RocketChatCache {
   public static final String KEY_SELECTED_SERVER_CONFIG_ID = "selectedServerConfigId";
   public static final String KEY_SELECTED_ROOM_ID = "selectedRoomId";
 
-  private static final String PUSH_ID = "pushId";
+  private static final String KEY_PUSH_ID = "pushId";
 
   /**
    * get SharedPreference instance for RocketChat application cache.
@@ -21,36 +21,16 @@ public class RocketChatCache {
     return context.getSharedPreferences("cache", Context.MODE_PRIVATE);
   }
 
-  public static String getSelectedServerConfigId(Context context) {
-    return get(context).getString(KEY_SELECTED_SERVER_CONFIG_ID, "");
-  }
-
-  public static void setSelectedServerConfigId(Context context, String serverConfigId) {
-    setString(get(context), KEY_SELECTED_SERVER_CONFIG_ID, serverConfigId);
-  }
-
-  public static String getSelectedRoomId(Context context) {
-    return get(context).getString(KEY_SELECTED_ROOM_ID, "");
-  }
-
-  public static void setSelectedRoomId(Context context, String roomId) {
-    setString(get(context), KEY_SELECTED_ROOM_ID, roomId);
-  }
-
-  public static String getPushId(Context context) {
+  public static String getOrCreatePushId(Context context) {
     SharedPreferences preferences = get(context);
-    String pushId = null;
-    if (!preferences.contains(PUSH_ID)) {
+    if (!preferences.contains(KEY_PUSH_ID)) {
       // generates one and save
-      pushId = UUID.randomUUID().toString().replace("-", "");
-      setString(preferences, PUSH_ID, pushId);
+      String newId = UUID.randomUUID().toString().replace("-", "");
+      preferences.edit()
+          .putString(KEY_PUSH_ID, newId)
+          .apply();
+      return newId;
     }
-    return preferences.getString(PUSH_ID, pushId);
-  }
-
-  private static void setString(SharedPreferences preferences, String key, String value) {
-    SharedPreferences.Editor editor = preferences.edit();
-    editor.putString(key, value);
-    editor.apply();
+    return preferences.getString(KEY_PUSH_ID, null);
   }
 }

app/src/main/java/chat/rocket/android/push/gcm/GcmRegistrationIntentService.java

@@ -52,8 +52,10 @@ public class GcmRegistrationIntentService extends IntentService {
       final User currentUser = realmHelper.executeTransactionForRead(realm ->
           User.queryCurrentUser(realm).findFirst());
 
-      new RaixPushHelper(getBaseContext(), serverConfig.getServerConfigId()).pushUpdate(
-          RocketChatCache.getPushId(this), gcmToken, currentUser != null ? currentUser.getId() : null)
+      final String pushId = RocketChatCache.getOrCreatePushId(this);
+      final String userId = currentUser != null ? currentUser.getId() : null;
+      new RaixPushHelper(getBaseContext(), serverConfig.getServerConfigId())
+          .pushUpdate(pushId, gcmToken, userId)
           .onSuccess(task -> {
             markRefreshAsDone(serverConfig);
             return task;

app/src/main/java/chat/rocket/android/service/observer/CurrentUserObserver.java

@@ -63,7 +63,9 @@ public class CurrentUserObserver extends AbstractModelObserver<User> {
     final String userId = user.getId();
 
     // update push info
-    pushHelper.pushSetUser(RocketChatCache.getPushId(context)).continueWith(new LogcatIfError());
+    pushHelper
+        .pushSetUser(RocketChatCache.getOrCreatePushId(context))
+        .continueWith(new LogcatIfError());
 
     // get and observe Room subscriptions.
     methodCall.getRoomSubscriptions().onSuccess(task -> {